B-mode enhancement at phase-inversion US with air-based microbubble contrast agent: initial experience in humans

Area of Science:

• Medical Imaging
• Ultrasound Technology
• Biomedical Engineering

Background:

• Traditional ultrasonography (US) has limitations in visualizing certain tissue characteristics.
• Microbubbles are effective contrast agents in US but their visualization can be challenging.
• Distinguishing between linear and nonlinear scattering is crucial for advanced US techniques.

Purpose of the Study:

• To evaluate the efficacy of pulse- or phase-inversion ultrasonography with a contrast agent.
• To assess the enhancement of normal and abnormal tissues using this advanced US technique.
• To explore the potential applications of this technology, particularly in tumor imaging.

Main Methods:

• Application of pulse- or phase-inversion ultrasonography with a US contrast agent.
• Summation of signals from two 180-degree ultrasound pulses.
• Analysis of signal voids from linear scattering and distinct signals from nonlinear microbubble scattering.
• Inclusion of 39 human subjects in the study.

Main Results:

• Consistent B-mode enhancement of vessels and organ parenchyma was observed in all subjects.
• Enhancement was achieved with both flowing and stationary microbubbles.
• Demonstrated flow-independent enhancement of both normal and abnormal tissues.
• Highlighted the distinct visualization of nonlinear microbubble signals against linear tissue signals.

Conclusions:

• Pulse- or phase-inversion ultrasonography with contrast agents significantly enhances tissue and vessel visualization.
• The technique's ability to visualize stationary microbubbles represents a major advancement in contrast-enhanced US.
• This method holds considerable promise for various clinical applications, notably in tumor imaging and characterization.